Fig. 1

Schematic figure of Y-shaped osteotomy in coronal plane: the apex vertebra was selected as center of osteotomy (A). Lamina, superior and inferior articular process, and pedicle, as well as 3/4 vertebral body on the convex side were removed (B). After gradually compression, convexity closing, concavity opening and a quarter of concave side preserving as the hinge, forming an inverted Y-shape (C)